import { useState } from 'react'
import { Link, useNavigate } from 'react-router-dom'
import { useAuth } from '../context/AuthContext'
import ThemeToggle from '../components/ThemeToggle'

export default function LoginPage() {
  const [username, setUsername] = useState('')
  const [password, setPassword] = useState('')
  const [error, setError] = useState('')
  const [isSubmitting, setIsSubmitting] = useState(false)
  const { login } = useAuth()
  const navigate = useNavigate()

  async function handleSubmit(e) {
    e.preventDefault()
    setError('')
    setIsSubmitting(true)
    try {
      await login(username, password)
      navigate('/dashboard')
    } catch {
      setError('Benutzername oder Passwort falsch.')
    } finally {
      setIsSubmitting(false)
    }
  }

  return (
    <div className="relative flex min-h-screen items-center justify-center bg-gray-50 px-4 dark:bg-gray-900">
      <div className="absolute right-4 top-4">
        <ThemeToggle />
      </div>
      <div className="w-full max-w-sm">
        <h1 className="mb-6 text-center text-2xl font-semibold text-gray-900 dark:text-gray-50">
          KalorienTracker
        </h1>
        <form
          onSubmit={handleSubmit}
          className="space-y-4 rounded-xl bg-white p-6 shadow-sm dark:bg-gray-800"
        >
          <div>
            <label className="mb-1 block text-sm font-medium text-gray-700 dark:text-gray-300">
              Benutzername
            </label>
            <input
              type="text"
              value={username}
              onChange={(e) => setUsername(e.target.value)}
              required
              autoFocus
              className="w-full rounded-lg border border-gray-300 px-3 py-2 text-base text-gray-900 focus:border-emerald-500 focus:outline-none dark:border-gray-600 dark:bg-gray-700 dark:text-gray-50"
            />
          </div>
          <div>
            <label className="mb-1 block text-sm font-medium text-gray-700 dark:text-gray-300">
              Passwort
            </label>
            <input
              type="password"
              value={password}
              onChange={(e) => setPassword(e.target.value)}
              required
              className="w-full rounded-lg border border-gray-300 px-3 py-2 text-base text-gray-900 focus:border-emerald-500 focus:outline-none dark:border-gray-600 dark:bg-gray-700 dark:text-gray-50"
            />
          </div>
          {error && <p className="text-sm text-red-600 dark:text-red-400">{error}</p>}
          <button
            type="submit"
            disabled={isSubmitting}
            className="w-full rounded-lg bg-emerald-600 py-2.5 text-base font-medium text-white active:bg-emerald-700 disabled:opacity-60"
          >
            {isSubmitting ? 'Anmelden…' : 'Anmelden'}
          </button>
        </form>
        <p className="mt-4 text-center text-sm text-gray-600 dark:text-gray-400">
          Noch kein Konto?{' '}
          <Link to="/register" className="font-medium text-emerald-600 dark:text-emerald-400">
            Registrieren
          </Link>
        </p>
      </div>
    </div>
  )
}